This invention relates to a simplified registration gate for selectively registering sheets fed seriatim in reproduction equipment such as a copier/duplicator or printer.
In high speed reproduction equipment, it is a general practice to make copies on individual sheets of material that are either cut from a web into desired sizes or located in a hopper. The sheets are fed seriatim and advanced along a travel path and into contact with an image bearing surface on a plate or web. The image is then transferred to the sheet and subsequently fused to the sheet. Since the image bearing surface may also be moving relative to the path of the individual sheet, the movement of the sheet must be synchronized and coordinated with the movement of the surface to insure correct registration for the image transfer.
Various types of sheet registration assemblies are well known in the art. For example, U.S. Pat. Nos. 4,019,732 and 4,019,733 disclose mechanisms for registering a copy sheet in reproduction equipment. The mechanisms described in these patents comprise a sheet travel path, means for advancing or urging the sheets along the path, and a registration device located on a hub that is mounted on a shaft and having at least a registration finger. The registration device is located on the hub between two rollers but interspaced from the rollers by thrust washers, so as to maintain an axial loading force on the registration device through the rollers. Each such mechanism consists of at least six separate components interacting and cooperating with each other and with the shaft.
Other known registration mechanisms have multiple interacting components. Typically, such mechanisms comprise a disc with a registration finger that is mounted on a hub (on a shaft) between two other discs, interacting with a pressure plate and a compressed spring on a support, to axially load the registration disc against a sheet feeding roller. Such multiple interacting component mechanisms that rely on axial loading against the sheet feeding rollers may be costly to assemble, difficult to adjust, and can be unreliable because of the axial loading. These disadvantages of the prior art are even more of a problem in high speed reproduction equipment that must also produce high quality copies. Such equipment requires a registration assembly with a registration gate that is easy to adjust but is accurate and reliable after adjustment, and a registration gate that is free of undesirable axial forces, and of the likelihood of component failure.